Percussion staff resulting from MIDI import shows key signature and accidentals

Ubuntu Studio 14.04, GIT commit: 6d46589

1) load attached MIDI file
2) drag treble clef to first bar of top (piano) staff

Result: unwanted accidentals appear on percussion staff

Or, instead of step 2) above, try:

2) drag G major key signature to first measure of top (piano) staff

Result: unwanted key signature appears on percussion staff (as well other staves, where it does belong of course)